Unit 5 Test Re-Review

When an atom gains or loses electrons, the charged particle that results is called _____.

• a molecule

  
  

• a polyatomic ion

• • 
    

    none of these

• an ion

When two pairs of electrons are shared between the atoms of a molecular compound, a _____ is
formed.

• ionic bond

• single bond

  
  

• diatomic bond

  
  

• double bond

  
  

Tags

NGSS.HS-PS1-1

Particles formed from the covalent bonding of atoms are called ions.

• True

• False

  
  

The oxidation number of an atom is shown with a ____. 

• superscript

• subscript

• positive number

  
  

• negative number

  
  

Which of the following is an example of a molecular (covalent) compound?

• H₂O

• none of these

  
  

• CaS

• MgBr₂

  
  

Tags

NGSS.MS-PS1-1

Explain what happens to the electrons in a polar covalent bond. They are ____. 

• none of these

  
  

• equally shared

  
  

• unequally shared

  
  

• transferred

  
  

Most ___ compounds are crystalline solids with high melting points. 

• non polar covalent

  
  

• polar & non polar covalent

  
  

• polar covalent

  
  

• ionic

Tags

NGSS.MS-PS1-4

When an atom gains or loses electrons, the charged particle that results is called a molecule.

• True

• False

In a chemical formula, the number of each type of atom in the compound is shown by numbers called
____.

• chemical symbols

  
  

• subscripts

• superscripts

• oxidation numbers

  
  

What is the correct formula for magnesium oxide? 

• Mg₂O₂

  
  

• MgO₂

• Mg₂O

• MgO

Tags

NGSS.MS-PS1-1